Abstract: Fire is an important driver of plant regeneration in global terrestrial ecosystems. Post-fire seed germination is a critical adaptive feature of plants in fire-prone environments. Smoke produced by pyrolysis of plant materials in wildfire contains various active chemical compounds, which can activate soil seed bank via initiating post-fire seed germination. Karrikins produced by cellulose pyrolysis are usually considered as the primary smoke cue that promotes seed germination. Recently, it has been found that lignin-promoted syringaldehyde can also trigger seed germination of post-fire plants. Here, we review the history of research on smoke cues and their ecological relevance to post-fire plant regeneration, and discuss the evolutionary aspects of smoke adaptation of plants. On basis of these discussions, we propose some important scientific questions about smoke-promoted seed germination to get some perspective on future research.

Key words: smoke cue, syringaldehyde, lignin, fire adaptation, post-fire germination